add typedoc-specific tsconfig

[sethvincent]

The only really interesting part about this is updating the package.json and adding a tsconfig.typedoc.json file: https://github.com/digidem/mapeo-schema/compare/fix-typedoc-tsconfig?expand=1#diff-7ae45ad102eab3b6d7e7896acd08c427a9b25b346470d7bc6507b6481575d519

Any improvements to the docs themselves that are being generated should be another issue/pr.

Closes #28

[gmaclennan]

Looks good to me. Small suggestion for tsconfig.

I'm wondering where it makes sense to include this in the build process? I noticed that the links that Typedoc generates under #### Defined In refer to s specific commit, so it seems like every time you run typedoc it changes the files.

Should we leave it the responsibility of the contributor to always re-build docs? Or run it as a commit hook? Or build on CI and push to a separate docs branch? or other?

[gmaclennan]

Since the generated docs are not useful at this time, and there is my unresolved question above about how we build docs and whether we commit them to main, I think it make sense to keep the docs folder ignored. Can you create a follow-up issue for what needs to be done for the docs to be useful?